CN111211209B - Ultraviolet light-emitting diode and manufacturing method thereof - Google Patents

Abstract

The application discloses an ultraviolet light emitting diode and a manufacturing method thereof, and relates to the technical field of light emitting diode production, including: a bracket; and the second electrode are located between the light-emitting chip and the bracket; the packaging structure includes at least one layer of packaging layer; the packaging layer covers the surface and side of the diode away from the bracket, and at least part of the packaging layer is in contact with the bracket; the refractive index of the packaging structure is θ, 1.0≤θ≤1.8; protective layer, the protective layer and the diode are located on the same side of the bracket, the protective layer surrounds the package structure, and the protective layer is in contact with the bracket. The present application can prevent the light-emitting chip from being corroded by air, water vapor, etc., and can improve the light-extraction efficiency of the ultraviolet light-emitting diode by arranging the encapsulation structure and the protective layer.

Description

Ultraviolet light-emitting diode and method of making the same

technical field

The present application relates to the technical field of light-emitting diode production, and in particular, to an ultraviolet light-emitting diode and a manufacturing method thereof.

Background technique

With the continuous advancement of light-emitting diode technology, in recent years, light-emitting diodes in the ultraviolet wavelength band have also received high attention. Ultraviolet light emitting diodes have the advantages of energy saving, environmental protection and high performance, and are widely used in lighting, medical treatment, printing, sterilization and other fields.

In the package structure of the ultraviolet light emitting diode, quartz glass with high light transmittance is usually used to protect the light emitting chip of the ultraviolet light emitting diode, so as to reduce the corrosion of the light emitting chip caused by the air and water vapor in the environment. However, when the UV light-emitting diode is a nitride-based UV-emitting diode with sapphire substrate, the refractive index of sapphire is approximately 1.8, the refractive index of nitride-based compound semiconductor is approximately 2.3, and the refractive index of quartz glass is approximately is 1.53, and the refractive index of air is approximately 1. Due to the large difference in refractive index, the reflectivity of light is high when it exits, so the light output efficiency will be reduced. In addition, in order to improve the light extraction efficiency and enhance the heat dissipation effect, the flip-chip bonding method is usually used. However, in the existing packaging structure of UV light emitting diodes, since there is no suitable covering colloid between the sapphire substrate and the quartz glass, the quartz glass There is a gap between the light-emitting chip and the light-emitting chip. When the light emitted by the light-emitting chip is emitted through one side of the sapphire substrate, the light is refracted multiple times between the air and the quartz glass, resulting in light loss and reduced light extraction efficiency.

SUMMARY OF THE INVENTION

In view of this, the present application provides an ultraviolet light emitting diode and a manufacturing method thereof. By arranging a package structure and a protective layer, the light emitting chip can be prevented from being corroded by air, water vapor, etc., and the light extraction efficiency of the ultraviolet light emitting diode can be improved.

In order to solve the above-mentioned technical problems, the application has the following technical solutions:

In one aspect, the present application provides an ultraviolet light emitting diode, comprising:

bracket;

a diode, the diode comprises a light-emitting chip, a first electrode and a second electrode electrically connected to the light-emitting chip, and the first electrode and the second electrode are located between the light-emitting chip and the support;

an encapsulation structure, the encapsulation structure includes at least one encapsulation layer; the encapsulation layer covers the surface and side surfaces of the diode away from the bracket, and at least part of the encapsulation layer is in contact with the bracket; the refraction of the encapsulation structure The coefficient is θ, 1.0≤θ≤1.8;

A protective layer, the protective layer and the diode are located on the same side of the bracket, the protective layer surrounds the package structure, and the protective layer is in contact with the bracket.

Optionally, where:

The material of the encapsulation structure includes at least one of hexamethyldisiloxane and silicon oxide.

Optionally, where:

The protective layer includes hydrophobic parylene.

Optionally, where:

The encapsulation structure includes a first encapsulation layer, and the first encapsulation layer includes a first hydrophobic group.

Optionally, where:

The refractive index of the first hydrophobic group is β1, where 1.3≤β1≤1.7.

Optionally, where:

The distance between the surface of the first encapsulation layer away from the diode and the surface close to the diode is h1, 400nm≤h1≤2000nm.

Optionally, where:

The encapsulation structure includes at least a second encapsulation layer and a third encapsulation layer; the third encapsulation layer is located on the side of the second encapsulation layer away from the diode; wherein,

The second encapsulation layer includes a first hydrophilic group, and the third encapsulation layer includes a second hydrophobic group.

Optionally, where:

The refractive index of the first hydrophilic group is β2, 1.43≤β2≤1.7;

The refractive index of the second hydrophobic group is β3, and 1.3≤β3≤1.5.

Optionally, where:

The distance between the surface of the second encapsulation layer away from the diode and the surface close to the diode is h2, 10nm≤h2≤100nm; the surface of the third encapsulation layer away from the diode and the surface close to the diode The distance between the surfaces is h3, 400nm≤h3≤2000nm.

On the other hand, the present application also provides a method for manufacturing an ultraviolet light emitting diode, comprising:

provide a stand;

A diode is arranged on the bracket, and the diode includes a light-emitting chip, a first electrode and a second electrode electrically connected to the light-emitting chip, and the first electrode and the second electrode are located on the light-emitting chip and the light-emitting chip. between the brackets;

A hydrophobic encapsulation structure is disposed on the side of the diode away from the bracket, the encapsulation structure includes at least one encapsulation layer, the encapsulation layer covers the surface and side of the diode away from the bracket, and at least part of the the encapsulation layer is in contact with the support;

A hydrophobic protective layer is coated on the bracket, the protective layer is located on the same side of the bracket as the diode, and the protective layer surrounds the encapsulation structure.

Compared with the prior art, the ultraviolet light emitting diode and the manufacturing method thereof described in the present application achieve the following effects:

(1) In the ultraviolet light emitting diode and its manufacturing method provided by this application, a package structure of one of hydrophobic hexamethyldisiloxane and hydrophobic silicon oxide is arranged on the diode, and the diode is completely connected to the outside world through the package structure. Air and water vapor are isolated to prevent the light-emitting chip from being corroded by air, water vapor, etc.; and the refractive index of the package structure is set between the air and the sapphire substrate. In this way, when the light-emitting chip emits light, the light is emitted to the package structure through the sapphire substrate, and the Compared with the outside air, the difference between the refractive index of the package structure and the refractive index of the sapphire substrate is small, which is beneficial to reduce the reflectivity of light between the sapphire substrate and the package structure, thereby improving the light extraction efficiency of the ultraviolet light emitting diode.

(2) In the ultraviolet light emitting diode and its manufacturing method provided by the present application, a hydrophobic protective layer is arranged on the bracket, the protective layer is in direct contact with the bracket, and the protective layer surrounds the encapsulation structure, so that the encapsulation structure can be further strengthened to shield the outside world The ability of water vapor, and has a certain fixing effect on the package structure, to avoid the problem of the package structure being not firmly bonded and falling off.

Description of drawings

The drawings described herein are used to provide further understanding of the present application and constitute a part of the present application. The schematic embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the attached image:

FIG. 1 shows a schematic structural diagram of an ultraviolet light emitting diode provided by an embodiment of the present application;

FIG. 2 shows another schematic structural diagram of the ultraviolet light emitting diode provided by the embodiment of the present application;

FIG. 3 shows a flow chart of the method for fabricating the ultraviolet light emitting diode provided by the embodiment of the present application;

Fig. 4 shows a test diagram of the output power change of a plurality of identical UV light emitting diodes when different packaging structures are set;

Fig. 5 shows the aging trend diagram of the UV light emitting diode when the encapsulation layer is not plated;

FIG. 6 is a graph showing the aging trend of the ultraviolet light emitting diode after the package structure provided by the present application is packaged.

Detailed ways

As used in the specification and claims, certain terms are used to refer to particular components. It should be understood by those skilled in the art that hardware manufacturers may refer to the same component by different nouns. The description and claims do not use the difference in name as a way to distinguish components, but use the difference in function of the components as a criterion for distinguishing. As mentioned in the entire specification and claims, "comprising" is an open-ended term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range, and basically achieve the technical effect. Furthermore, the term "coupled" herein includes any direct and indirect means of electrical coupling. Therefore, if a first device is described as being coupled to a second device, it means that the first device can be directly electrically coupled to the second device, or indirectly electrically coupled through other devices or coupling means connected to the second device. Subsequent descriptions in the specification are preferred embodiments for implementing the present application. However, the descriptions are for the purpose of illustrating the general principles of the present application and are not intended to limit the scope of the present application. The scope of protection of this application should be determined by the appended claims.

In the package structure of the ultraviolet light emitting diode, quartz glass with high light transmittance is usually used to protect the light emitting chip of the ultraviolet light emitting diode, so as to reduce the corrosion of the light emitting chip caused by the air and water vapor in the environment. However, when the UV light-emitting diode is a nitride-based UV-emitting diode with sapphire substrate, the refractive index of sapphire is approximately 1.8, the refractive index of nitride-based compound semiconductor is approximately 2.3, and the refractive index of quartz glass is approximately is 1.53, and the refractive index of air is approximately 1. Due to the large difference in refractive index, the reflectivity of light is high when it exits, so the light output efficiency will be reduced. In addition, in order to improve the light extraction efficiency and enhance the heat dissipation effect, the flip-chip bonding method is usually used. However, in the existing packaging structure of UV light emitting diodes, since there is no suitable covering colloid between the sapphire substrate and the quartz glass, the quartz glass There is a gap between the light-emitting chip and the light-emitting chip. When the light emitted by the light-emitting chip is emitted through one side of the sapphire substrate, the light is refracted multiple times between the air and the quartz glass, resulting in light loss and reduced light extraction efficiency.

In view of this, the present application provides an ultraviolet light emitting diode and a manufacturing method thereof. By arranging a package structure and a protective layer, the light emitting chip can be prevented from being corroded by air, water vapor, etc., and the light extraction efficiency of the ultraviolet light emitting diode can be improved.

The following detailed description will be given in conjunction with the accompanying drawings and specific embodiments.

FIG. 1 is a schematic structural diagram of an ultraviolet light emitting diode 100 provided by an embodiment of the present application. Please refer to FIG. 1. The ultraviolet light emitting diode 100 provided by an embodiment of the present application includes:

bracket 110;

Diode 120, the diode 120 includes a light-emitting chip 121, a first electrode 122 and a second electrode 123 electrically connected to the light-emitting chip 121, and the first electrode 122 and the second electrode 123 are located between the light-emitting chip 121 and the bracket 110;

an encapsulation structure 130, the encapsulation structure 130 includes at least one encapsulation layer; the encapsulation layer covers the surface and side surfaces of the diode 120 away from the bracket, and at least part of the encapsulation layer is in contact with the bracket 110;

The protective layer 140 is located on the same side of the bracket 110 as the diode 120 , the protective layer 140 surrounds the package structure 130 , and the protective layer 140 is in contact with the bracket 110 .

Specifically, the ultraviolet light emitting diode 100 provided in the embodiment of the present application includes a bracket 110 and a diode 120, wherein the diode 120 is disposed on the bracket 110 and is a flip-chip light emitting diode, including a light-emitting chip 121 and a first electrode 122, The second electrode 123, the first electrode 122 and the second electrode 123 are located between the light-emitting chip 121 and the support 110, and both the first electrode 122 and the second electrode 123 are electrically connected to the light-emitting chip 121 through the first electrode 122 and the second electrode 123. The electrode 123 provides a voltage signal to the light-emitting chip 121, for example, the first electrode 122 provides a positive voltage signal to the light-emitting chip 121, and the second electrode 123 provides a negative voltage signal to the light-emitting chip 121, passing between the first electrode 122 and the second electrode 123 The voltage difference drives the light-emitting chip 121 to emit light.

The ultraviolet light emitting diode 100 includes an encapsulation structure 130 , the diode 120 is located between the encapsulation structure 130 and the bracket 110 , the encapsulation structure 130 includes an encapsulation layer, and there is a part of the encapsulation layer in direct contact with the bracket 110 , that is, the encapsulation layer completely covers the diode 120 In this way, the diode 120 can be isolated from the outside air and water vapor, so as to prevent the light-emitting chip 121 from being corroded by air, water vapor and the like. The light-emitting chip 121 includes a sapphire substrate, and light is emitted from one side of the sapphire substrate. The refractive index of the sapphire substrate is approximately equal to 1.8, and the refractive index of air is approximately equal to 1.0. In the present application, the refractive index θ of the package structure 130 is set between the air and the sapphire substrate of the light-emitting chip 121 , that is, θ is greater than or equal to 1.0 and less than or equal to 1.8. When the light-emitting chip 121 emits light, the light is emitted to the packaging structure 130 through the sapphire substrate. Compared with the outside air, the difference between the refractive index of the packaging structure 130 and the refractive index of the sapphire substrate is small, which is beneficial to reduce the amount of light between the sapphire substrate and the sapphire substrate. The reflectivity between the package structures 130 can improve the light extraction efficiency of the diode 120 .

The UV light emitting diode 100 further includes a protective layer 140 . In the viewing angle shown in FIG. 1 , the diode 120 and the protective layer 140 are both located above the bracket 110 , the protective layer 140 is in direct contact with the bracket 110 , and the protective layer 140 surrounds the package structure 130 In this way, the ability of the packaging structure 130 to shield external water vapor can be further enhanced, and the packaging structure 130 can be fixed to a certain extent, so as to avoid the problem that the packaging structure 130 is not firmly adhered and falls off.

Optionally, the protective layer includes hydrophobic parylene. Specifically, in this application, the protective layer 140 is made of hydrophobic parylene. Since parylene has a strong barrier effect, parylene also has acid and alkali corrosion resistance, dissolution resistance and freezing resistance. Therefore, the use of parylene to form the protective layer 140 is more conducive to enhancing the ability of the packaging structure 130 to shield external water vapor, and can also improve the resistance to acid and alkali corrosion of the ultraviolet light emitting diode 100 . Parylene can be prepared by chemical vapor deposition method. When the protective layer 140 is made of parylene, it can be coated on surfaces of various shapes to form a uniform film, and the process is relatively simple and easy to operate, which is conducive to reducing operation difficulty and cost.

Optionally, referring to FIG. 1 , the material of the encapsulation structure 130 includes hexamethyldisiloxane. Specifically, hexamethyldisiloxane has high light transmittance, which will not affect the light of light-emitting diodes while achieving encapsulation, and hexamethyldisiloxane is a colorless and transparent liquid. The ratio of silicon to oxygen can change its hydrophobicity and hydrophilicity. For example, when the ratio of silicon and oxygen is close to 2:3, it is hydrophilic, has affinity for water, and is easily soluble in water; When the ratio is close to 1:2, it is hydrophobic, repelling water and not easily soluble in water. Therefore, in this embodiment, hexamethyldisiloxane is used to make the encapsulation structure 130, and the proportion of silicon and oxygen in the hexamethyldisiloxane can be adjusted according to actual needs to make it hydrophobic. The light-emitting chip 121 is corroded by air, water vapor, and the like. In addition, the refractive index of hexamethyldisiloxane is between the sapphire substrate and the outside air. Therefore, the refractive index of the package structure 130 formed by using hexamethyldisiloxane is also between the sapphire substrate and the outside air. In between, the difference between the refractive index of the package structure and the refractive index of the sapphire substrate is small, which is beneficial to reduce the light reflectivity, thereby improving the light extraction efficiency of the diode 120 .

Optionally, please refer to FIG. 1 , the material of the package structure 130 includes silicon oxide. Specifically, similar to the performance of hexamethyldisiloxane, silicon oxide has high light transmittance, which will not affect the light of the light-emitting diode while encapsulating, and can be changed by adjusting the ratio of silicon to oxygen. Its hydrophobicity and hydrophilicity, for example, when the ratio of silicon and oxygen is close to 2:3, silicon oxide is hydrophilic, has an affinity for water, and is easily soluble in water; when the ratio of silicon and oxygen is close to 1:2 , silica is hydrophobic, repelling water, and is not easily soluble in water. Therefore, in this embodiment, silicon oxide is used to make the package structure 130, and the ratio of silicon to oxygen in the silicon oxide can be adjusted according to actual needs to make it hydrophobic, so that the light-emitting chip 121 can be prevented from being corroded by air and water vapor. In addition, the refractive index of silicon oxide is between the sapphire substrate and the outside air. Therefore, the refractive index of the package structure 130 formed by using silicon oxide is also between the sapphire substrate and the outside air, so that the refractive index of the package structure 130 is also between the sapphire substrate and the outside air. The difference between the refractive index and the sapphire substrate is small, which is beneficial to reduce the light reflectivity, thereby improving the light extraction efficiency of the diode 120 .

Optionally, referring to FIG. 1 , the encapsulation structure 130 includes a first encapsulation layer 131 , and the first encapsulation layer 131 includes a first hydrophobic group. Specifically, please refer to FIG. 1 . In this embodiment, the package structure 130 is formed by a layer of package layer, which is called the first package layer 131 . In order to protect the diode 120 from being corroded by water and oxygen, the package structure 130 needs to have a shielding water and oxygen layer. performance, that is, the first encapsulation layer 131 should be able to block water and oxygen intrusion. Therefore, in this embodiment, by adjusting the ratio of silicon to oxygen in the first encapsulation layer 131 to be 1:2, there is no oxygen vacancy in the first encapsulation layer 131, and the first encapsulation layer 131 is close to the crystal structure. When an encapsulation layer 131 is in contact, the lattice oxygen in the first encapsulation layer 131 repels water molecules, and the water molecules cannot infiltrate the first encapsulation layer 131 , so that the diode 120 can be well protected from external water and oxygen through the first encapsulation layer 131 . Corrosion increases the service life of the diode 120 .

It should be noted that, the first encapsulation layer 131 in this embodiment can be any one of hexamethyldisiloxane and silicon oxide in the above-mentioned embodiments. In actual use, it can be selected according to needs. The application is not limited in this regard.

Optionally, please refer to FIG. 1 , the refractive index of the first hydrophobic group is β1, where 1.3≤β1≤1.7. Specifically, referring to FIG. 1 , when the packaging structure 130 includes only one packaging layer, that is, the first packaging layer 131 , in order to protect the diode 120 from being corroded by water and oxygen in the outside air, the first packaging layer 131 needs to have In fact, when fabricating the diode 120 , not only the service life of the diode 120 but also the light extraction efficiency of the diode 120 should be considered. In order to improve the light extraction efficiency of the diode 120 , in this embodiment, the refractive index of the first hydrophobic group in the first encapsulation layer 131 is set to be greater than or equal to 1.3 and less than or equal to 1.7, so that the refractive index of the encapsulation structure 130 can be guaranteed to be between the air and the sapphire substrate. In between, the difference between the refractive index of the package structure 130 and the refractive index of the sapphire substrate is minimized, which is beneficial to reduce the reflectivity of light between the sapphire substrate and the package structure 130 , thereby improving the light extraction efficiency of the diode 120 .

It should be noted that the value range of the refractive index of the first hydrophobic group set in this embodiment is only a schematic illustration, and is not intended to limit the application. In the actual production process, the first hydrophobic group The index of refraction can be specifically set according to the material of the package structure 130 . For example, when the first encapsulation layer 131 is made of hexamethyldisiloxane, the refractive index can be any value greater than or equal to 1.3 and less than or equal to 1.7; and when the first encapsulation layer 131 is made of silicon oxide, the refractive index can be Any value greater than or equal to 1.3 and less than or equal to 1.5. However, it should be noted that no matter which material is used to make the packaging layer, its refractive index must be between that of air and the sapphire substrate, so as to ensure that the difference in refractive index between the packaging structure 130 and the sapphire substrate is smaller than that between the packaging structure 130 and the sapphire substrate. The difference in refractive index between them is beneficial to reduce the reflectivity of the sapphire substrate and improve the light extraction efficiency.

Optionally, please refer to FIG. 1 , the distance between the surface of the first encapsulation layer 131 away from the diode 120 and the surface close to the diode 120 is h1 , 400nm≦h1≦2000nm. Specifically, in order to ensure that the encapsulation structure 130 can completely cover the diode 120 , in this embodiment, the encapsulation thickness of the first encapsulation layer 131 is set to be greater than or equal to 400 nm, and the thickness here refers to the direction perpendicular to the plane where the protective layer 140 is located. When the coating thickness of the first encapsulation layer 131 is greater than or equal to 400 nm, it can ensure that the diode 120 is completely covered, thereby achieving the purpose of complete waterproofing and preventing the diode 120 from being corroded by external water and oxygen. When fabricating the package structure 130, in addition to the waterproof problem, the light emitting rate of the diode 120 should also be considered, and if the thickness is too thick, the light emitted by the light-emitting chip 121 may be attenuated in the package structure 130. The thickness of the encapsulation layer 131 is greater than or equal to 400 nm and less than or equal to 2000 nm. In this way, the diode 120 can be prevented from being corroded by external water and oxygen, and the light can be prevented from being attenuated in the encapsulation structure 130 , which is beneficial to improve the light extraction efficiency of the diode 120 .

It should be noted that the coating thickness of the first encapsulation layer 131 is greater than or equal to 400 nm and less than or equal to 2000 nm, which is only an implementation in this embodiment, and is not intended to limit this application. When the coating thickness of the first encapsulation layer 131 is greater than 100 nm, the diode 120 can be covered. Therefore, in other embodiments, the coating thickness range of the first encapsulation layer 131 can also be set to other values. In addition, as shown in FIG. 1 , the cladding thickness of each position of the first encapsulation layer 131 may be different, as long as it is ensured that the first encapsulation layer 131 can completely cover the light-emitting chip 121 .

Optionally, FIG. 2 shows another schematic structural diagram of the ultraviolet light emitting diode 100 provided by the embodiment of the present application. Please refer to FIG. 2 , the packaging structure 130 at least includes a second packaging layer 132 and a third packaging layer 133; The third encapsulation layer 133 is located on the side of the second encapsulation layer 132 away from the diode 120 ; wherein, the second encapsulation layer 132 includes a first hydrophilic group, and the third encapsulation layer 133 includes a second hydrophobic group. Preferably, the refractive index of the first hydrophilic group is β2, 1.43≤β2≤1.7; the refractive index of the second hydrophobic group is β3, 1.3≤β3≤1.5.

Specifically, please refer to FIG. 2 , in this embodiment, the encapsulation structure 130 is configured to consist of two layers of encapsulation layers, which are the second encapsulation layer 132 and the third encapsulation layer 133 respectively, and the second encapsulation layer 132 is configured to have hydrophilicity, wherein The refractive index of the first hydrophilic group is greater than or equal to 1.43 and less than or equal to 1.7, the third encapsulation layer 133 has hydrophobicity, and the refractive index of the second hydrophobic group is greater than or equal to 1.3 and less than or equal to 1.5. In this way, the encapsulation structure 130 is performed. During fabrication, the second encapsulation layer 132 can be plated first, and then the third encapsulation layer 133 can be plated. Since the refractive index of the second encapsulation layer 132 is between the sapphire substrate and the third encapsulation layer 133, the second encapsulation layer 132 can To a certain transition effect, it is beneficial to reduce the refractive index difference between the sapphire substrate and its adjacent structures, thereby further reducing the reflectivity of the sapphire substrate and improving the light extraction efficiency. The hydrophilicity and hydrophobicity of the encapsulation layer here can also be adjusted by the ratio of silicon to oxygen in the encapsulation layer, which will not be repeated here.

It should be noted that the value ranges of the refraction coefficients of the first hydrophilic group and the second hydrophobic group set in this embodiment are only a schematic illustration, and are not intended to limit the application. , the refractive index of the two can be specifically set according to different materials used in the packaging structure 130 . For example, when the encapsulation structure 130 is made of hexamethyldisiloxane, the refractive index of the first hydrophilic group can be any value greater than or equal to 1.45 and less than or equal to 1.7, and the second hydrophobic group can be greater than or equal to 1.3 and less than is equal to any value in 1.5; and when the encapsulation structure 130 is made of silicon oxide, the refractive index of the first hydrophilic group can be any value greater than or equal to 1.43 and less than or equal to 1.5, and the second hydrophobic group can be greater than or equal to 1.4 Less than or equal to any value in 1.48. However, it should be noted that no matter which material is used to make the encapsulation layer, it must be ensured that the second encapsulation layer 132 is hydrophilic, the third encapsulation layer 133 is hydrophobic, and the refractive index of the third encapsulation layer 133 is smaller than that of the second encapsulation layer In this way, the second encapsulation layer 132 can play a transitional role and further improve the light extraction efficiency.

Optionally, please refer to FIG. 2 , the distance between the surface of the second encapsulation layer 132 away from the diode 120 and the surface close to the diode 120 is h2, 10nm≤h2≤100nm; the third encapsulation layer 133 is away from the surface of the diode 120 and close to The distance between the surfaces of the diodes 120 is h3, 400nm≤h3≤2000nm. Specifically, please refer to FIG. 2 , when fabricating the package structure 130 , in addition to the waterproof problem, the light extraction rate of the diode 120 should also be considered, and if the thickness is too thick, the light emitted by the light-emitting chip 121 may be attenuated in the package structure 130 . Therefore, in this embodiment, the coating thickness h2 of the second packaging layer 132 is set to be greater than or equal to 10 nm and less than or equal to 100 nm, and the coating thickness h3 of the third packaging layer 133 is set to be greater than or equal to 400 nm and less than or equal to 2000 nm. thickness in the direction of the plane where the protective layer 140 is located. In this way, it can be ensured that the diode 120 is completely covered, so as to achieve the purpose of complete waterproofing, prevent the diode 120 from being corroded by external water and oxygen, and avoid the problem that the light emitted by the light-emitting chip 121 is attenuated in the package structure 130 due to excessive thickness. It is beneficial to improve the light extraction efficiency of the diode 120 .

It should be noted that the coating thicknesses of the second encapsulation layer 132 and the third encapsulation layer 133 in the above-mentioned embodiments are only a schematic illustration, and are not intended to limit the present application. In other embodiments, the second encapsulation layer The cladding thicknesses of 132 and the third encapsulation layer 133 may also be set to other values.

Based on the same inventive concept, an embodiment of the present application also provides a method for fabricating an ultraviolet light emitting diode 100. FIG. 3 shows a flowchart of the method for fabricating an ultraviolet light emitting diode 100 provided by the embodiment of the present application. Please refer to 1-3, the manufacturing method of the ultraviolet light emitting diode 100 provided by the embodiment of the application includes:

Step 10: providing a bracket 110;

Step 20: Disposing a diode 120 on the support 110, the diode 120 includes a light-emitting chip 121, a first electrode 122 and a second electrode 123 electrically connected to the light-emitting chip 121, and the first electrode 122 and the second electrode 123 are located between the light-emitting chip 121 and the support between 110;

Step 30 : disposing an encapsulation structure 130 on the side of the diode 120 away from the bracket 110 , the encapsulation structure 130 includes at least one hydrophobic encapsulation layer, the encapsulation layer covers the surface and side of the diode 120 away from the bracket, and at least part of the encapsulation layer is in contact with the bracket 110 ;

Step 40 : Coating a hydrophobic protective layer 140 on the bracket 110 , the protective layer 140 and the diode 120 are located on the same side of the bracket 110 , and the protective layer 140 surrounds the encapsulation structure 130 .

Specifically, referring to FIGS. 1 to 3 , in the method for fabricating the ultraviolet light emitting diode 100 provided by the embodiment of the present application, a bracket 110 is first provided, and then the diode 120 is arranged on the bracket 110 in step 20, in order to improve the light output Efficiency and effective heat dissipation, the diode 120 is set as a flip-chip structure, that is, the first electrode 122 and the second electrode 123 are located between the light-emitting chip 121 and the bracket 110, and the first electrode 122 and the second electrode 123 are both electrically connected to the light-emitting chip 121. connection, the first electrode 122 and the second electrode 123 provide a voltage signal to the light-emitting chip 121, for example, the first electrode 122 provides a positive voltage signal to the light-emitting chip 121, and the second electrode 123 provides a negative voltage signal to the light-emitting chip 121, The voltage difference between the first electrode 122 and the second electrode 123 drives the light-emitting chip 121 to emit light.

After the diode 120 is set, a package structure 130 is set in step 30. The diode 120 is located between the package structure 130 and the bracket 110. The package structure 130 includes a package layer, and some of the package layers are in direct contact with the bracket 110, that is, the package layer The diode 120 is completely covered, so that the diode 120 can be isolated from the outside air and water vapor, thereby preventing the light-emitting chip 121 from being corroded by air, water vapor, and the like. The light-emitting chip 121 includes a sapphire substrate, and light is emitted from one side of the sapphire substrate. The refractive index of the sapphire substrate is approximately equal to 1.8, and the refractive index of air is approximately equal to 1.0. In the present application, the refractive index θ of the package structure 130 is set between the air and the sapphire substrate of the light-emitting chip 121 , that is, θ is greater than or equal to 1.0 and less than or equal to 1.8. When the light-emitting chip 121 emits light, the light is emitted to the packaging structure 130 through the sapphire substrate. Compared with the outside air, the difference between the refractive index of the packaging structure 130 and the refractive index of the sapphire substrate is small, which is beneficial to reduce the amount of light between the sapphire substrate and the sapphire substrate. The reflectivity between the package structures 130 can improve the light extraction efficiency of the diode 120 .

In step 40, a hydrophobic protective layer 140 is coated on the bracket 110, the diodes 120 and the protective layer 140 are both located above the bracket 110, the protective layer 140 is in direct contact with the bracket 110, and the protective layer 140 surrounds the encapsulation structure 130. In this way, it is possible to The ability of the packaging structure 130 to shield external water vapor is further enhanced, and it has a certain fixing effect on the packaging structure 130 to avoid the problem that the packaging structure 130 is not firmly adhered and falls off.

The output power changes and waterproof results of various packaging methods in the ultraviolet light emitting diode provided by the present application will be described below with reference to the test data.

Fig. 4 shows a test chart of the output power change of a plurality of identical UV light emitting diodes when different packaging structures are set. Table 1 shows the average value of the output power change of the UV light emitting diodes in the four embodiments shown in Fig. 4 .

Table 1 Comparison table of output power changes of various packaging methods of UV light emitting diodes

Example Hydrophilic film thickness Hydrophobic film thickness Hydrophilic film thickness Average power variation 1 100nm 700nm 0 +7.8% 2 100nm 500nm 0 +8.2% 3 0 800nm 0 +7.6% 4 100nm 600nm 100nm +6.4%

Referring to Table 1 and FIG. 4, it can be seen that different encapsulation structures are set for the same ultraviolet light emitting diode, and the output power of the ultraviolet light emitting diode is different. When the encapsulation structure includes two encapsulation layers, and the first encapsulation layer is hydrophilic, the third When the second encapsulation layer is hydrophobic, the output power of the ultraviolet light emitting diode is relatively high. Combining Example 1 and Example 2, it can be seen that when the first encapsulation layer is hydrophilic, the second encapsulation layer is hydrophobic, and the thickness of the first encapsulation layer is smaller than the thickness of the second encapsulation layer, the output of the ultraviolet light emitting diode Highest power.

FIG. 5 shows the aging trend diagram of the UV light emitting diode when the package layer is not plated, and FIG. 6 shows the aging trend diagram of the UV light emitting diode after the package structure provided by the application is packaged. The UV light emitting diode plated with the encapsulation layer ages obviously faster than the UV light emitting diode plated with the encapsulation layer. It can be seen that the encapsulation structure provided by the present application can significantly increase the service life of the UV light emitting diode.

It can be known from the above embodiments that the beneficial effects of the present application are:

(1) In the ultraviolet light emitting diode provided by the application and the manufacturing method thereof, an encapsulation structure is arranged on the ultraviolet light emitting diode, and the ultraviolet light emitting diode is completely isolated from the outside air and water vapor by the encapsulation structure, so as to prevent the light-emitting chip from being damaged by air and water vapor. Equal corrosion; and set the refractive index of the package structure to be between the air and the sapphire substrate, so that when the light-emitting chip emits light, the light is emitted to the package structure through the sapphire substrate. Compared with the outside air, the refractive index of the package structure is the same as the sapphire substrate. The difference in the refractive index of the substrate is small, which is beneficial to reduce the reflectivity of light between the sapphire substrate and the package structure, thereby improving the light extraction efficiency of the ultraviolet light emitting diode.

(2) In the ultraviolet light emitting diode and its manufacturing method provided by the present application, a hydrophobic protective layer is arranged on the bracket, the protective layer is in direct contact with the bracket, and the protective layer surrounds the encapsulation structure, so that the encapsulation structure can be further strengthened to shield the outside world The ability of water vapor, and has a certain fixing effect on the package structure, to avoid the problem of the package structure being not firmly bonded and falling off.

It should be understood by those skilled in the art that the embodiments of the present application may be provided as a method, an apparatus, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various and other combinations, modifications and environments, and can be modified within the scope of the inventive concepts described herein, from the above teachings or from skill or knowledge in the relevant art. However, modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present application, and should all fall within the protection scope of the appended claims of the present application.

Claims (8)

1. An ultraviolet light emitting diode, comprising:

a support;

the LED comprises a light-emitting chip, a first electrode and a second electrode, wherein the first electrode and the second electrode are electrically connected with the light-emitting chip and are positioned between the light-emitting chip and the bracket; the light emitting chip comprises a sapphire substrate, and light rays are emitted from one side of the sapphire substrate;

a package structure comprising at least one package layer; the packaging layer covers the surface and the side face of the diode far away from the support, and at least part of the packaging layer is in contact with the support; the refractive index of the packaging structure is between air and the sapphire substrate, the refractive index of the packaging structure is theta, and theta is more than or equal to 1.0 and less than or equal to 1.8; the packaging structure is made of a material at least comprising one of hexamethyldisiloxane and silicon oxide; the packaging structure comprises a hydrophobic material;

the protective layer and the diode are positioned on the same side of the support, the protective layer surrounds the packaging structure, and the protective layer is in contact with the support; the protective layer includes hydrophobic parylene.

2. The UV LED of claim 1,

the encapsulation structure includes a first encapsulation layer including a first hydrophobic group.

3. The UV LED of claim 2,

the refractive index of the first hydrophobic group is beta 1, wherein beta 1 is more than or equal to 1.3 and less than or equal to 1.7.

4. The UV LED of claim 2, wherein the distance between the surface of the first encapsulation layer away from the diode and the surface close to the diode is h1, 400nm ≦ h1 ≦ 2000 nm.

5. The UV LED of claim 1,

the packaging structure at least comprises a second packaging layer and a third packaging layer; the third packaging layer is positioned on one side of the second packaging layer far away from the diode; wherein,

the second encapsulation layer includes a first hydrophilic group and the third encapsulation layer includes a second hydrophobic group.

6. The UV LED of claim 5,

the refractive index of the first hydrophilic group is beta 2, and beta 2 is more than or equal to 1.43 and less than or equal to 1.7;

the refractive index of the second hydrophobic group is beta 3, and beta 3 is more than or equal to 1.3 and less than or equal to 1.5.

7. The UV LED of claim 5,

the distance between the surface of the second packaging layer far away from the diode and the surface of the second packaging layer close to the diode is h2, and h2 is more than or equal to 10nm and less than or equal to 100 nm; the distance between the surface of the third packaging layer far away from the diode and the surface close to the diode is h3, and h3 is more than or equal to 400nm and less than or equal to 2000 nm.

8. The method for manufacturing the ultraviolet light emitting diode as claimed in any one of claims 1 to 7, comprising:

providing a bracket;

arranging a diode on the bracket, wherein the diode comprises a light-emitting chip, a first electrode and a second electrode which are electrically connected with the light-emitting chip, and the first electrode and the second electrode are positioned between the light-emitting chip and the bracket; the light emitting chip comprises a sapphire substrate, and light rays are emitted from one side of the sapphire substrate;

arranging a hydrophobic packaging structure on one side of the diode, which is far away from the support, wherein the packaging structure comprises at least one packaging layer, the packaging layer covers the surface and the side face of the diode, which are far away from the support, and at least part of the packaging layer is in contact with the support; the refractive index of the packaging structure is between air and the sapphire substrate, the refractive index of the packaging structure is theta, and theta is more than or equal to 1.0 and less than or equal to 1.8; the packaging structure is made of a material at least comprising one of hexamethyldisiloxane and silicon oxide; the packaging structure comprises a hydrophobic material;

coating a hydrophobic protective layer on the support, wherein the protective layer and the diode are positioned on the same side of the support, and the protective layer surrounds the packaging structure; the protective layer includes hydrophobic parylene.

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